Over the past decade, protein A affinity chromatography has become well established as the primary method of choice for the capture of monoclonal antibodies (mAbs) from mammalian cell culture feed streams. This highly specific affinity step is able to remove 98% of impurities in a single step due to the specific binding between the protein A ligand and the Fc-region of the antibody. Under typical operating conditions in protein A chromatography, clarified cell culture feed streams are applied to the column until a certain load mass of antibody is achieved. The column is then typically washed with a high ionic strength buffer to remove host cell contaminants bound to the resin through nonspecific interactions. The antibody is then normally eluted from the column by a shift in pH and collected for further processing. The primary objective of this work is therefore to investigate the use of detergents combined with salts to disrupt both ionic and hydrophobic interactions and enhance removal of host cell contaminants, thereby reducing the purification burden on downstream unit operations.
For large-scale purification much effort is placed on optimizing the components of wash and elution buffers to maximize product yield. However, in a production situation where many different protein products are being purified at the same time, developing a unique wash buffer for each individual protein product requires significant time and resources to screen various buffer components to determine an appropriate wash buffer for each particular protein product. A “generic” intermediate wash buffer that could be used effectively with different types of proteins would be useful and desirable. The present invention provides a method of protein purification using such wash buffer components.